Summary: Immune cell interactions are critical in HIV pathogenesis. These interactions involves in antigen presentation between antigen presenting cells and T lymphocytes, capturing and transmission of virus from monocyte and dendritic cells to resting T cells, and depletion of CD4 cells through cell membrane receptors which are involved in apoptosis pathways. The study in my laboratory will focus on the determination of the critical molecules on immune cells involved in HIV transmission and depletion of CD4 T cells, and the regulation of the gene expression of these molecules by viral components. The experiments will be performed both in vitro using cell culture system and in vivo using human/SCID reconstitution system. The pathogenesis of HIV-1/2 subtypes in induction of T cell apoptosis will be studied. The cytokine and chemokine productions will be also analyzed. The research in my laboratory will also extend to the study of the pathogenesis of human herpes virus 8 (HHV8), the etiologic factor for Kaposi's sarcoma. Kaposi's sarcoma is the most commune neoplasma occurring in individuals with AIDS, especially in homosexual AIDS patients. The study is designed to test whether HIV is involved in the induction of replication of HHV8, and to identify the molecular interactions between HIV and HHV8. This project is highly relevant to the mission of DETTD regarding the issue of transmission of HHV8 through blood transfusion and organ transplantation.